Electric circuit breaker with pushbutton for tripping

ABSTRACT

An electric circuit breaker with a recessed pushbutton operable to move an armature member and an ambient temperature compensating bimetallic latching member endwise. Because of the manner in which the armature member is mounted, the members are also rotated to move the free end of the latching member out of latching relationship with a releasably latchable trip lever releasable to effect separation of a pair of contacts.

United States Patent Kenneth W. Erickson Cedar Rapids. Iowa 858,348

Sept. 16, 1969 June 15, 1971 Square D Company Park Ridge, lll.

lnventor Appl. No. Filed Patented Assignee ELECTRIC CIRCUIT BREAKER WITHPUSl-IBUTTON FOR TRIPPING 2 Claims, 5 Drawing Figs.

U.S. CL 335/45, 3 37/66 Int. Cl. H0lh 71/12 Field of Search 335/43, 45,42, 37', 337/66 [56] References Cited UNITED STATES PATENTS 2,952,757 9/1960 Ellenberger 337/66 3,061,697 10/1962 Kralik 335/37 3,275,959 9/1966Locher 335/45 Primary Examiner-Harold Broome Attorneys-Harold J. Rathbunand Paul J. Rose ABSTRACT: An electric circuit breaker with a recessedpushbutton operable to move an armature member and an ambienttemperature compensating bimetallic latching member endwise. Because ofthe manner in which the armature member is mounted, the members are alsorotated to move the free end of the latching member out of latchingrelationship with a releasably latchable trip lever releasable to effectseparation of a pair of contacts.

ELECTRIC CIRCUIT BREAKER WITH PUSI-IBU'ITON FOR TRIPPING An object ofthe invention is to provide a push-to-trip feature for a circuit breakerhaving an armature member, a latching member, and a magnetic core memberconstructed and arranged generally as in the circuit breaker disclosedin U.S. Pat. No. 3,06l,697, which is hereby incorporated herein byreference.

In the drawings, FIG. I is a fragmentary front view of a circuit breakerconstructed in accordance with the invention;

FIG. 2 is an enlarged perspective view of the pushbutton of the circuitbreaker of FIG. I;

FIG. 3 is a fragmentary side view of the circuit breaker of FIG. 1, theside cover having been removed and the trip lever being shown in latchedposition;

FIG. 4 is a view similar to FIG. 3, but showing the trip lever intripped position; and

FIG. 5 is an enlarged fragmentary sectional view of a portion of FIG. 4.

- Parts of the circuit breaker of this invention substantially identicalto the parts of the circuit breaker of U.S. Pat. No. 3,061,697 areidentically numbered, and reference may be had to the patent for acomplete description.

In accordance with this invention, a pushbutton member 80 isreciprocally mounted in the base 12 adjacent the opening for the handle25. The member 80 includes an outer end portion 80a (FIG. 2) and aninner portion 80b. The outer surface of the portion 800 is normallysubstantially flush with the outer surface of the surrounding portion ofthe base 12, as can be noted in FIG. 3. The inner portion 80b is widerthan the portion 80a and presents a shoulder at 800 (FIG. 2) forengagement with an inner surface of the base 12 to limit outwardmovement of the member 80. The inner end of the portion 80b is providedwith a recess 80d for reception of the adjacent joined ends of thebimetallic armature 64 and the ambient temperature compensatingbimetallic strip 73.

The finger portion 68 extends at an angle from the main portion of thearmature 64 through the slot 69 in the portion 70 of the magnetic core51. When the push button member is depressed, as in FIG. 4, the mainportion of the armature 64 is moved longitudinally, but because thefinger portion 68 is confined in the slot 69 in the magnetic coreportion 70, the armature 64 is also rotated counterclockwise toward themagnetic core 51 from the position of FIG. 3 to the position of FIG. 4.The amount of movement is relatively small, but it is sufficient to movethe bimetallic strip 73 out of latching relationship with the releasablylatchable trip lever 34, just as when the armature 64 is magneticallyattracted toward the magnetic core 5 I.

lclaim:

1. In an electric circuit breaker having a casing, a pair of separablecontacts in the casing, a releasably latchable trip lever pivotallymounted in the casing and releasable from a latched position to effectseparation of the contacts, a terminal strap extending into the casing,a bimetallic strip secured adjacent one end to an inner end portion ofthe terminal strap, a magnetizable core in the casing secured to thebimetallic strip and having an extension with a slot therein, anelongated generally flat armature in the casing pivotally mountedadjacent one end on the core, extending generally parallel to thebimetallic strip, and having a finger portion at the other end extendingat an angle to the remainder thereof through the slot in the extensionof the core, and an elongated generally flat latching member in thecasing secured adjacent one end to the one end of the armature,extending generally parallel to the armature and to the bimetallicstrip, and normally latching the trip lever with the other end portionthereof, the improvement comprising a pushbutton extending into thecasing in endwise alignment with the armature and latching memberadjacent their joined ends and depressible'to move the armature andlatching member longitudinally and pivot the t ri lever while the angledfinger portion of the armature IS gui ed by the extension of the core tocause pivotal movement of the armature and latching member anddisengagement of the latching member from the trip lever.

2. An electric circuit breaker as claimed in claim I, wherein thearmature and latching member are bimetallic strips.

1. In an electric circuit breaker having a casing, a pair of separablecontacts in the casing, a releasably latchable trip lever pivotallymounted in the casing and releasable from a latched position to effectseparation of the contacts, a terminal strap extending into the casing,a bimetallic strip secured adjacent one end to an inner end portion ofthe terminal strap, a magnetizable coRe in the casing secured to thebimetallic strip and having an extension with a slot therein, anelongated generally flat armature in the casing pivotally mountedadjacent one end on the core, extending generally parallel to thebimetallic strip, and having a finger portion at the other end extendingat an angle to the remainder thereof through the slot in the extensionof the core, and an elongated generally flat latching member in thecasing secured adjacent one end to the one end of the armature,extending generally parallel to the armature and to the bimetallicstrip, and normally latching the trip lever with the other end portionthereof, the improvement comprising a pushbutton extending into thecasing in endwise alignment with the armature and latching memberadjacent their joined ends and depressible to move the armature andlatching member longitudinally and pivot the trip lever while the angledfinger portion of the armature is guided by the extension of the core tocause pivotal movement of the armature and latching member anddisengagement of the latching member from the trip lever.
 2. An electriccircuit breaker as claimed in claim 1, wherein the armature and latchingmember are bimetallic strips.